Supersensitization with bis-heterocyclic bases



g-' 1958' J. J. CHECHAK ETAL 2,848,329

SUPERSENSI-TIZATIONWITH BIS-HETEROCYCLIC BASES Filed May 14, 1956 A:5,5; DIETHYLTHIA DICARBOCYANINE IODIDE a.= 5,3 DIETHYLTHIADICARBOCYANINEIODIDE WITH |,4-[2- (-5 PHENYLOXAZOLYU] BENZENE v C2D 'llll HLWMH 1m m m300 4-00 '4 500 600 700 c=s,s- DIETHYlIHIADICARBOCYANINE IODIDE =3,3'-DIETHYIJ'HIADICARBOCYANINE IODIDE WITH L215 (2- a ENZOTHIAZOLYL) ETHYLENE =3,3:- DIETHYLOXAIDICARBOCYANINE IODIDE F 3,3 DIETHYLOXADICARBOCYANINEIODIDE WITH |,4- BIS [2- (5- PHENYLOXAZOLYD] BENZENE 76120811 C/zechak Je an E. Jones INVENTORS moRNm llnitd tates SUPERSENSITIZATIGN WITHBlS-HETEROCYCLIC BASES Jonas John Chechak and Jean E. Jones, Rochester,N. Y., assignors to Eastman Kodak Company, Rochester, N. Y., acorporation of New Jersey Application May 14, 1956, Serial No. 584,544

10 Claims. (Cl. 96-104) This invention relates to photographic silverhalide emulsions useful in color photography and photographic silverhalide emulsions containing dicarbocyanine dyes, and as supersenitizerstherefor, certain heterocyclic bases.

It is known in the art of making photographic emulsions that certaindyes of the cyanine class alter the sensitivity of photographicemulsions of the gelatinosilver-halide kind, when the dyes areincorporated in the emulsions. It is also known that the sensitizationproduced by a given dye varies somewhat with the type of emulsion inwhich the dye is incorporated. Furthermore, the sensitization of a givenemulsion by a given dye may be altered by varying the conditions in theemulsion. For example, the sensitization may be increased by increasingthe silver ion concentration or decreasing the hydrogen ionconcentration (i. e., increasing the alkalinity) or both. Thus,sensitization can be increased by bathing plates, coated with aspectrally sensitized emulsion, in Water or in acqueous solutions ofammonia. Such a process of altering the sensitivity of a sensitizedemulsion by increasing the silver ion concentration and/or by decreasingthe hydrogen ion concentration is commonly called hypersensitization.Hypersensitized emulsions have generally poor keeping qualities.

We have now found another means of altering the sensitivity in emulsionscontaining dicarbocyanine dyes. Since the conditions in the emulsion, i.e., the hydrogen ion and/or the silver ion concentration undergo littleor no change in our method, we shall designate our method as a kind ofsupersensitization.

It is, therefore, an object of our invention to provide photographicemulsions containing dicarbocyanine dyes and, as supersensitizerstherefore, certain heterocyclic bases. Another object is to provide aprocess for preparing these supersensitized emulsions. Other objectswill become apparent from a consideration of the following descriptionand examples.

The dicarbocyanine dyes which are useful in practicing our inventioninclude those represented by the following general formula:

2,848,329 Patented Aug. 19, 1958 ice benzothiazole,6-chlorobenzothiazole, 7-chlorobenzothia zole, 4-methylbenzothiazole,S-methylbenzothiazole, 6- methylbenzothiazole, 5 bromobenzothiazole, 6bromobenzothiazole, 4-phenylbenzothiazole, 5-phenylbenzothiazole,4-methoxybenzothiazole, 5 -methoxybenzothiazole, 6 methoxybenzothiazole,6 iodobenzothiazole, 5 iodobenzothiazole, 4-ethoxybenzothiazole,S-ethoxybenzothiazole, 5,6-dimethylbenzothiazole,S-hydroxybenzothiazole, 6-hydroxybenzothiazole, etc.), a heterocyclicnucleus of the naphthothiazole series (e. g., or naphthothiazole,B-naphthothiazole, 7-methoxy-tx-naphthothiazole, S-methoxy anaphthothiazole, 5 methoxy-{B-naphthothiazole,S-ethoxy-a-naphthothiazole, etc.), a heterocyclic nucleus of thebenzoselenazole series (e. g., benzoselenazole, 5 chlorobenzoselenazole,6 methoxybenzoselenazole, S-methoxybenzoselenazole, etc.), aheterocyclic nucleus of the naphthoselenazole series (e. g.,wnaphthoselenazole, fi-naphthoselenazole, etc.), a heterocyclic nucleusof the benzoxazole series (e. g., benzoxazole, S-hydroxybenzoxazole,6-hydroxybenzoxazole, S-chlorobenzoxazole, S-methoxybenzoxazole,o-methoxybenzoxazole, S-phenylbenzoxazole, S-bromobenzoxazole, etc.), aheterocyclic nucleus of the naphthoxazole series (e. g.,ot-naphthoxazole, fi-naphthoxazole, etc.), a heterocyclic nucleus of theZ-quinoline series (e. g., Z-quinoline, 6-methyl-2-quinoline,7-methyl-2-quinoline, 8-methy1-2-quinoline, 6-chlo ro-2-quinoline,8-chloro-2-quinoline, 4-chloro-2-quinoline, 5 ethoxy-Z-quinoline, 6ethoxy-Z-quinoline, 7-ethoXy-2- quinoline, fi-hydroxy-Z-quinoline,7-hydroXy-2-quinoline, 6-methoxy-2-quinoline, etc.), a heterocyclicnucleus of the 4-quinoline series (e. g., 4-quinoline, 6-methoxy-4-quinoline, 7-methyl-4-quinoline, 8-methyl-4-quinoline, etc.), aheterocyclic nucleus of the benzimidazole series (e. g., benzimidazole,S-chlorobenzimidazole, 5,6-dichlorobenzimidazole,1,7-trimethylenebenzimidazole, etc.), a heterocyclic nucleus of the5,6-benzoquinoline series (e. g., 5,6-benzo-2-quinoline, etc.), etc.,and-Z represents the non-metallic atoms necessary to complete aheterocyclic nucleus selected from the group consisting of those of thequinoline series (e.g., such as those defined by Z above), those of thebenzoxazole series (e. g., such as those defined by Z above), those ofthe naphthoXazole series (e. g., such as those defined by Z above),those of the benzoselenazole series (e. g., such as those defined by Zabove), those of the naphthoselenazole series (e. g., such as thosedefined by Z above), those of the benzothiazole series (e. g., such asthose defined by Z above), those of the naphthothiazole series (e. g.,such as those defined by Z above), etc. Other dicarbocyanine dyes canalso be employed in our invention.

The heterocyclic bases useful in practicing our invention compriseheterocyclic nitrogen bases containing from 1 to 2 nitrogen atoms andhaving a substituent attached thereto which contains at least fourcarbon atoms. Such heterocyclic bases comprise those advantageouslyrepresented by the following general formula: (II) Zg I N b-Rz whereinZ; represents the non-metallicatoms necessary to 7 complete aheterocyclic nucleus containing from 1 to 2 quinoline series, etc.), andR represents an organic radi-' cal containing at least 4 carbon atoms,said radical hav- 3 ing a molecular weight of at least 71. Embraced bythe above general Formula II are the bis-heterocyclyl compoundsrepresented by the following general formula:

(III) ,Z, //Z2\\ bi C(D)d-1 iv wherein Z has the values given above, drepresents a positive integer of from 1 to 2, and D represents adivalent organic radical, such as dithiaalkylene (e. g., u,wcliihiaalkylene groups, such as u,w-dithiapropylene, a,wdithiabutylene,a,w-dithiapentylene,' etc., especially such groups containing from 1 tocarbon atoms), alkylene (e. g., methylenqethylene, propylene, butylene,pentylene, hexylene, etc., especially such groups containing from 1 tocarbon atoms), arylene (e. g., phenylene, biphenylene, benzylene,bis(phenylene)methyl, etc., especially such groups containing from 6 to13 carbon atoms), vinylene, thio, oxyclimethylene, etc. Typicalbisheterocyclyl compounds represented by Formula III include thefollowing:

1 ,5-bis (2-benzothiazo1y1thio) pentane 1,2-bis Z-benzothiazolyl) ethaneC-CHzCHzCHr-C 1,3-bis (2-benzothiazolyl propane 1 ,4-bis(2-benzothiazo1y1) butane 1,5-bis (2-benzothiazo1y1) pentane N N Bis(2-benzothiazo1y1thio) methane 1,2-bis (2-benzothiazo1ylthio) ethane0-8-0 Q Bis (2-benzoth1azoly1) sulfide (9) Bis [4 (2-benzothiazoly1)phenyl] methane 1,4-bis 2-a-naphthothiazo1yl) butane n R n HHH/ 1 Bis(Z-a-naphthothiazolyl) methane p,a-Bis 2-benzothiazo1yl) toluene 1,4bis(Z-benzimidazolyl benzene 1,2-bis (2-benzimid azolyi) ethylene 2-(2-benzothiazolyl)benzothiazole 1,5-b1s (2-benzoxazo1y1) pentane 1,2-bis(2-benzimidazo1y1thio) ethane hydrobromide 1,2-bis (2-benzothiazolyl)ethylene Also embraced by Formula 11 above are heterocyclic basesselected from those represented by the following general formula:

wherein Z has the values given above and R represents an alkyl group (e.g., amyl, heXyl, octyl, decyl, dodecyl, etc., especially an alkyl groupcontaining from 5 to 12 carbon atoms), an aryl group (e. g., phenyl, m-,and p-tolyl, 0-, m-, and p-anisyl, 0-, rn-, and p-arninophenyl,p-dimethylaminophenyl, p-diethylaminophenyl, etc., especially amononuelear aromatic group of the benzene series), an aralkyl group (e.g., benzyl, ,Ci-phenylethyl, etc.), an aryloxyalkyl group (e. g.,phenoxymethyl, fiphenoxyethyl, etc.), an acylamido group (e. g., amidotoluarnido, acetacetarnido, valerarnido, benzamido, etc., especially anacylamido group containing from 4 to 9 carbon atoms), alkylmercapto,arylrnercapto, a substituted amino group (e. g., butylarnino, anilino,tolylamino, etc.), and a substituted imino group. Bases ernbraced byFormula IV include the following:

( s Q t 2- (p-anisylybenzothiaz ole O-CsHs Z-phenylbenzothiazole 24 S OO H ll C-N-CC Hr-C-C Ha N 2-acetacetamidobenzothiazole C-CHsCHz-CaHa N2- (B-phenylethyl benzothiazole C-CHz-O-CaHa2-phenoxymethy1benzothiazole butyr- 2-[-1-(2-amin0-5-methy1phenylaz0)pheny1]benzothiaz 1e 2-4-dimethy1aminophenyl benzothiazole C-N=O HO H=O Cells 2-(3-ethy1-2(3H)-benzothiazolylidene)ethylideneJaminobenzothiazole C S CaHs 2-pheny1mercaptobenzoxazole C S C EH11 2-n-octylmereaptobenzothiazole f N S 03H 2-(4-amino-3-sulfopheny1)-6-methy1benzothiazo1e4,4=-his 2- (G-methylbenzothiazolyl) ]-N,N-diphenylurea-2,2' disulfonicacid As shown above, the heterocyclic nuclei represented by Z of FormulaII above can have substituents thereon which do not interfere with thephotographic emulsion. Such substituents can be alkyl groups, such asmethyl, ethyl, etc., aryl groups, such as phenyl, tolyl, etc.,

halogen atoms, such as chlorine, bromine, ete., alkoxyl,

' 7 groups, such as methoxyl, ethoxyl, etc., hydroxyl, amino, etc.

According to our invention, we incorporate one or more of thedicarbocyanine dyes represented by Formula I above with one or moreheterocyclic bases, such as those represented by Formulas II, III or IVabove. Our invention is particularly directed to the ordinarily employedgelatino-silver-halide emulsions. However, our supersensitizingcombinations can be employed in silver halide emulsions in which thecarrier is other than gelatin, e. g., a resinous substance or cellulosicmaterial which has no deteriorating effect on the light-sensitivematerials. The dicarbocyanine dyes and heterocyclic bases can beemployed in various concentrations depending upon the eifects desired.

Ordinarily, the optimum or near optimum concentration of thedicarbocyanine dyes which we employ in practicing our invention is ofthe order of from 0.010 to 0.30 g. per mol. of silver halide in theemulsion.

The heterocyclic bases which we employ in our invention canadvantageously be employed at a concentration of from about 0.05 to 1.0g. per mol. of silver halide in the emulsion.

In general, the ratio of concentration of dicarbocyanine dye toheterocyclic base can vary rather widely in our combinations, e. g.,from 1:5 to 1:100 (by weight) in many cases.

The methods of incorporating sensitizing dyes and heterocyclic bases insilver halide emulsions are well known to those skilled in the art.While the dicarbocyanine dyes and heterocyclic bases can be directlydispersed in the emulsions, it is convenient to add the same in the formof solutions in appropriate solvents. Methanol, ethanol, pyridine, andthe like have proven satisfactory for many of the dyes of Formula I andbases of Formulas II, III and IV. Mixtures of solvents, e. g., pyridinediluted with methanol or acetone, can also be used. The dicarbocyaninedyes and heterocyclic bases are dispersed in the finished emulsions andshould be uniformly distributed throughout the emulsions. The followingprocedure is satisfactory: Stock solutions of the dicarbocyanine dyesand heterocyclic bases are prepared by dissolving the same inappropriate solvents as described above. Then, to the flowablegelatino-silver-halide emulsion, the desired amounts of the stocksolution of one of the dyes (or heterocyclic bases) are slowly added.While stirring the emulsion. Stirring is continued until the dye isthoroughly incorporated in the emulsion. Then the desired amount of thestock solution of the heterocyclic base (or dye, if heterocyclic basehas been added first) is slowly added to the emulsion, while stirring.Stirring is continued until the second solution is thoroughlyincorporated. The supersensitized emulsion can then be coated out on asuitable support. such as glass, cellulose derivative film, resin film,or paper, to a suitable thickness and allowed to dry. The details ofsuch coating methods are well known to those skilled in the art. Theforegoing procedures and proportions are to be regarded only asillustrative. Clearly, our invention is directed to any silver halideemulsion containing a combination of the alforesaid dicarbocyanine dyesand heterocyclic bases whereby a supersensitizing efiect is obtained.

The following examples will serve to illustrate further the manner ofpracticing out invention.

In Table I below, to difierent portions of the same batch ofphotographic gelatino-silver-bromiodide emulsion were added (1) adicarbocyanine dye, such as those represented by Formula I above, and(2) a combination of the dicarbocyanine dye and heterocyclic base. Thenthe emulsions were held at about 5052 C. for a short time and coated ona support, chill set, and dried. After exposure through a Wratten No. 25filter, i. e., a filter which transmits substantially no light ofwavelength shorter than about 580 mu. in an Eastman Type lb sensistometer, the film strips were processed for 3 minutes in a developerhaving the following composition:

Water to make 1 liter.

The speed (red), gamma and fog for each of the coatings was thenmeasured. The results are recorded in Table I. I

TABLE I Red Light Exposure sensitizing Dye and Base (gJmol. Example AgX)Bil/E Gam- Fog Speed ma (a) 3,3'-diethyloxathiadicarbocya 4.35 1.54 .06

nine iodide (.045 (b) dye (a) (.045) plus base 1 (.30)..- 10.6 2. 48 06{(0) dye (d) (.045) 3. 85 1.21 .06 (d) dye (a) (.045) plus base 6(.15).-. 7. 55 1. .06 (e) dye ((1 (.045) plus base 7 (.15) 8. 2. l6 06(I) dye (a) (.045) plus base 28 (.15) 29. 5 3. 18 .00 (g) dye (a) (.045)plus base 8 (.15)-.. 10.4 2.40 .06 (h) dye (a) (.045) plus base 9(.15)... 15.4 2. 70 .06 (2') dye (a) (.045) plus base 10 (.15). 8. 252.48 .06 (j) dye (a) (.045) plus base 11 (15).. 15.8 1.92 .06 {(k) dye(a) (.045) 4. 25 1. 52 .06 (I) dye (a) (.045) plus base 29 (.15)-.. 27.5 2. 62 .06 (m) dye (a) (.045) plus base 12 (.15). 11.4 2. 64 .06 (n)dye (a) (.045) plus base 13 (.15). 11.4 2. 72 .06 (o) dye (a) (.045)plus base 14 (15).. 9. 5 2.10 .06 {(p) dye (11) (.045) 4.05 1.30 .06 (q)dye (a) (.045) plus base 2 (.15)-.. 5. 6 1.84 .06 (r) dye (a) (.045)plus base 3 (15).... 12. 5 2.7 .06 (s) dye (a) (.045) plus base 4(.15).. 7. 2 2.1 .06 (t) dye (a) (.045) plus base 5 (.15). 7.9 2.32 .06(u) dye (a) (.045) 5.8 2.0 .06 (v) dye (a) (.045) plus base 17 (.15)...7. 2 2.0 .06 (w) 3,3'-di-B-hydroxyethylthiadicar- (i. 40 1. 05

boeyaniue bromide (.045). (I) dye (w) (.045) plus base 29 (15).. 13. 72. 40 06 (y) dye (to) (.045) plus base 28 (.15)- 19.0 2. 70 .05 (z)3,3-diethylthiadicarbocyanine 5.6 2.1 .05

iodide (.045). (a) dye (z) (.045) plus base 21a (.15).. 7.6 2. 7 .05(b') dye (z) (.045) plus base 16 (.15)-.. 25. 5 3.1 .05 (c)3,3'-diethylseleuadicarbocyauine- 2. 7 2. 9 .06 iodide (.045).

(d') dye (c) (.045) with base 21a (.15). 6.0 2. 4 .05 (e) dye (6) (.045)with base 16 (.15).. 10. 9 3. 1 05 (f) 3,3-dicthyl-4,5,4,5-dibsnzo- 5.63.1 .10

thiadioarboeyanine iodide (.045). (g') dye (f) (.045) plus base 16(.15).. 20. 5 3. 0 .07 (h') 3,3-diethyloxadicarbocyanine 7. 6 3. 2 .07

iodide (.045). (i') dye (h) (.045) plus base 16 (.15).. 15. 8 3.1 .07 (j1,1-dimethyl-2,2-dicarbocyaui.ue 2.8 2. 4 .34

romide (.045). (1.1) dye (3") plus base 16 (.15) 8.8 2.8 .12 {(1') dye(a) (.045)... 4.05 1. 30 .06 (m) dye (a) (.045) plus base 30 (15).. 14.7 2. 60 06 (n) dye (a) (.045) plus base 31 (.15).. 15.4 3. 1 .06 {(0')dye (a) (.045) 4.15 1.89 .08 (p) dye (a) (.045) plus base 32 (.15)6.9 1. 30 .06 {(q) dye (a) (.045) 4. 6 1. 9 .06 (I') dye (a) (.045) plusbase 22 (15).. 17. 3 2. 6 .06 (s') dye (a) (.045) plus base 19 (.15)..6.3 2. 2 .05 (t) dye (a) (.045) plus base 20 (.15).- 9. 3 3.0 .06 {(u')dye (a) (.045) 4. 0 2. 3 00 (v) dye (a) (.045) plus base 23 (15).. 7.02. 2 .05 (w) dye (a) (.045) plus base 24 (.15). 7. 4 2. 4 .06 (I) dye(a) (.045) plus base 25 (.15).. 14. 4 3. 1 .06 (y) dye (a) (.045) plusbase 26 (.15).. 45. 5 2.9 .06 (2) dye (a) (.045) plus base 21 (15).. 9.92.4 .06 (11") dye (a) (.045) plus base 15 (15).. 16. 9 2. 8 .06 (0) dye(a) (.045) plus base 27 (.l5). l0. 4 2. 3 .06 {(c) dye (a) (.045) 2.0 50.05 (d") dye (a) (.045) plus base 18 (.32) 18. 0 1. 8 06 In the abovetable, the coatings of Examples 2, 3, -4, 5, 6, 7, and 8 were made fromthe same batch of emulsion, the coatings of Examples 9, 10, 11, and 12were made from the same batch of emulsion, the coatings of Examples 13,14, 15, and 16 were made from the same batch of emulsion, the coatingsof Examples 18 and 19 were made from the same batch of emulsion, thecoatings of Examples 20 and 21 were made from the same batch ofemulsion, the coatings of Examples 22 and 23 were made from the samebatch of emulsion, the coatings of Examples 27 and 28 were made from thesame batch of emulsion, the coatings of Examples 30, 31, and 32 weremade from the same batch of emulsion, and the coatings of Examples 33 to39 were made from the same batch of emulsion. No measurements ofcoatings containing only the heterocyclic bases of Formula II alone aregiven, since numerous coatings at the concentration used in the tablehave shown that these bases alone have little or no measurablesensitizing effect on the emulsions.

Our invention is primarily directed to the ordinarily employedgelatino-silver-halide developing-out emulsions, e. g.,gelatino-silver-chloride, -chlorobromide, -ch1oroiodide,-chlorobromiodide, -bromide and -bromidide developing-out emulsions.Emulsions which form the latent image mostly inside the silver halidegrains, such as the emulsions set forth in U. S. Patent 2,456,956, datedDecember 21, 1948, can also be employed in practicing our invention.

The emulsions prepared in accordance with our invention can be coated inthe usual manner on any suitable support, e. g., glass, cellulosenitrate film, cellulose acetate film, polyvinyl-acetal resin film, paperor metal.

Photographic silver halide emulsions, such as those listed above,containing the supersensitizing combinations of our invention can alsocontain such addenda as chemical sensitizers, e. g., sulfur sensitizers.(e. g., allyl thiocarbamide, thiourea, allylisothiocyanate, cystine,etc),

various gold compounds (e. g., potassium chloroaurate, aurictrichloride, etc.) (see U. S. Patents 2,540,085; 2,597,856 and2,597,915), various palladium compounds, such as palladium chloride (U.S. 2,540,086), potassium chloropalladate (U. 2,598,079), etc., ormixtures of such sensitizers; anti-foggants, such as ammoniumchloroplatinate (U. S. 2,566,245), ammonium chloroplatinite (U. S.2,566,263), benzotriazole, nitrobenzimidazole, 5- nitroindazole,benzidine, mercaptans, etc. (see Mees--- The Theory of the PhotographicProcess, Macmillan Pub., 1942, page 460), or mixtures thereof;hardeners, such as formaldehyde (U. S. 1,763,533), chrome alum (U. S.1,763,533), glyoxal U. S. 1,870,354), dibromacrolein (Br. 406,750), etc;color couplers, such as those described in U. S. Patent 2,423,730,Spence and Carroll U. S. Patent 2,640,776, etc.; or mixtures of suchaddenda. Dispersing agents for color couplers, such as those set forthin U. S. Patents 2,322,027 and 2,304,940, can also be employed in theabove-described emulsions.

Such silver halide emulsions can also contain thiazolidones or otherultraviolet absorbing compounds, such as those described in Sawdy U. S.Patent 2,739,888, issued March 27, 1956. While certain emulsion addenda,such as certain ultraviolet compounds, and certain color-formingcompounds cause desensitization or un-sensitizing effects, it has beenfound that the new combinations of our invention largely overcome sucheffects. Typical color-forming compounds which can he so employedinclude those in U. S. Patent 2,322,027 and the following:

Coupler:

(l) l-hydroxy-2-[8-(2,4'-di-tert.amylphenoxy) nbutyll-naphthamide (U. S.Patent 2,474,293) (2) 1-hydroxy-4-phenylazo-4'-(p tert.butylphenoxy)-2-naphthanilide (U. S. Patent 2,521,908) (3)2-(2,4-di-tert.-amylphenoxyacetamino)-4,6 dichloro-S-methyl phenol(Graham U. S. Patent 2,725,291)

(4) 2-(u-di-tert.amylphenoxy-mbutyrylamino) 4,6-

dichloro-t-methyl phenol (5) 6-{0L-{4i:0L-(2,4 ditert.amylphenoxy)butyramido]-phenoxy}acetamido} 2,4 dichloro 3- methylphenol (6) 2-[3 (2",4 diamylphenoxy)acetamidolbenzamido4-chloro-5-methyl phenol (7)*1-(2,4,6'-trichlorophenyl)-3 [3"(2',4"-ditert.amylphenoxyacetamido)benzamidol 5- pyrazolone (U. S. Patent 2,600,788)

(8) 1-(2',4,6-trichlorophenyl)-3-[3"-(2,4ditertampylphenoxyacetamido)-benzamidol-4 (pmethoxyphenylazo) -5 -pyrazolone (9) N-(4 benzoylacetaminobenzenesulfonyl) N- (y-phenylpropyl) ptoluidine (U. S. Patent 2,298,443)

('10) a-o-methoxybenzoyl-a-chloro 4-[u (2,4 ditert.-amylphenoxy)-nbutyramido] acetanilide (McCrossen, U. S. Patent 2,728,658)

(11) ot-{3 [a (2,4 di tert.amylphenoxy)acetamido]-benzoyl}-2-methoxyacetanilide (12) 3-benzoylacetamido-4-methoxy-2',4'di tert.

amylphenoxy acetanilide ("13) 4-benzoylacetamido-3-metl1oxy-2,4 ditert.-

amylphenoxy acetanilide The following table and examples will serve toillustrate the beneficial effects of our new supersensitizingcombinations when employed in a photographic emulsion containing adispersion of a coupler or color-forming compound. In Table II, theseeffects are illustrated for an ordinary photographicgelatino-silver-bromiodide emulsion containing3,3'-diethyloxathiadicarbocyanine iodide (50 mg./mol. AgX). To oneportion of the sensitized emulsion was added a coupler dispersioncontaining coupler No. 5 of the above list, while no coupler dispersionwas added to the second portion. To an aliquot of each of these portionsof emulsion was added a heterocyclic base as identified in the followingtable. Each of the emulsions was then digested for a short time at 50C., coated, chill set and exposed in an Eastman Type lb sensitomcterthrough a Wratten No. 25 filter as in the case of the coatings for TableI. The coatings containing the coupler dispersion were held at 40 C. forone-half hour before coating onto the film base and subsequent exposure.The exposed coatings were then developed for about 3 minutes in adeveloper having the composition indicated above with respect toTable 1. After exposure and development of the coatings, the relativered speed, gamma, and fog for the coatings was measured. The results aregiven in Table II below.

Speed Gamma Fog Speed Gamma Fog none 3 7 .04 21 46 .12 35 (4.0) 535 5 1.04 3.0 .07 none 100 2 9 .05 36 2.0 .14 36 (0.4) 395 3 6 .05 280 2.7 .12

The bis compounds represented by Formula III above are to bedistinguished from his compounds containing a substituent on thenitrogen atom shown in Formula 111, such as the following compounds:

C H3 CH3 Bis (3-1nethyl-2 (3H -benzothiazolylldene) acetone (39) I S NCN s C=CH CC H=C I r C2Hs C2 [Bis (3-ethy1-2 (3H -be.nzothiazolylidene)is opropylidene] malonitrile (40) S /S (I l CH3 C a 1,4-bis[ (3-methyl-2(3H) -benzothiazolylidene) amino] benzene Compounds 37-40 above can alsobe employed advantageously in combination with the dicarbocyanine dyesof our invention, such as dye (a) of Table I. Such compounds as 3740above have chemical properties distinct from the heterocyclic bases ofour invention. It is to be further understood that in ascertaining theheterocyclic bases of our invention as set forth above, suchheterocyclic bases contain not more than 2 nitrogen atoms in anyheterocyclic ring, i. e., from 1 to 2 nitrogen atoms in any heterocyclicring. As noted above, R of Formula IV can represent an alkylmercaptogroup, such groups including butylmercapto, hexylmercapto,octylmercapto, decylmercapto, dodecylmercapto, etc., (especiallyalkylmercapto groups containing from 4 to 12 carbon atoms). R of FormulaIV can also represent an arylmercapto group as noted above, includingphenylmercapto, tolylmercapto, etc., (especially an arylmercapto groupcontaining from 4 to 7 carbon atoms). Particularly useful substitutedimino groups (R of Formula IV include (heterocyclylidene) ethylidenegroups wherein the heterocyclic nucleus is the same or difierent type ofheterocyclic nucleus represented by Z The accompanying drawingillustrates the supersentitizing eifect obtained with three of our newcombinations in gelatino-silver-bromiodide emulsions. Each figure of thedrawing is a diagrammatic reproduction of two spectrograms. Thesensitivity of the emulsion containing only the dicarbocyanine dye ofFormula I is represented by the solid curve, while the sensitivity ofthe same emulsion containing both a dicarbocyanine dye of Formula I anda heterocyclic base, such as is represented by Formulas II, III or IV,is represented by the broken line. No curve representing the sensitivityof the heterocyclic base alone is shown, since numerous coatings at theconcentrations shown in the table have indicated that these heterocyclicbases have little or no measurable sensitizing action of their own.

In Fig. 1, curve A represents the sensitivity of an ordinarygelatino-silver-bromiodide emulsion sensitized with3,3-diethylthiadicarbocyanine iodide, while curve B represents thesensitivity of the same emulsion sensitized with3,3'-diethylthiadicarbocyanine iodide and 1,4-bis[2-(5phenyloxazolyl)]benzene. Sensitometric measurements for these coatingsare given in Example 21 of Table I.

In Fig. 2, curve C represents the sensitivity of an ordinarygelatino-silver-bromiodide emulsion sensitized with3,3'-diethylthiadicarbocyanine iodide, while curve D represents thesensitivity of the same emulsion sensitized with3,3-diethylthiadicarbocyanine iodide and 1,2-bis(2-benzothiazolyl)ethylene. Sensitometric measurements for these coatingsare given in Example of Table I.

In Fig. 3, curve B represents the sensitivity of an ordinarygelatino-silver-bromiodide emulsion sensitized with3,3'-diethyloxadicarbocyanine iodide, while curve F represents thesensitivity of the same emulsion sensitized with3,3-diethyloxadicarbocyanine iodide with 1,4-bis [2-(5phenyloxazolyl)lbenzene. Sensitometric measurements for these coatingsare given in Example of Table I.

Many of the heterocyclic bases represented by Formulas II, III and IVabove have been previously described in the prior art. Listed below arereferences describing the method whereby a number of these compounds canbe prepared, together with the melting point of these products incertain cases.

Chem. Abs, 47 (1953), 2750 Ber. 13, 21 and Ber. 46, 97

.T.A. .s.,73,(1951 1093 U. S. 2,739,96 L

The following examples describe the preparation of a number of theseheterocyclic bases which can be employed in our invention.

Example A .-2- [4- (2-amin0-5-methylphenylazo) phenyl] benzothiazole Asolution of 0.8 g. of sodium nitrite in 5 ml. of Water was addeddropwise to a cold (5 C.) suspension of 2.26 g. of2-p-aminophenylbenzothiazole in 50 ml. of water containing 4 ml. ofconcentrated hydrochloric acid. The reaction mixture was allowed tostand in the cold for one hour, then diluted to 500 ml. with ice waterand 0.5 g. of urea was added. The reaction mixture was filtered and theclear cold filtrate was added to 1.07 g. of ptoluidine dissolved in 5ml. of pyridine. After standing for several hours the crystals werecollected on a filter. The yield of product was 81% crude and 50% aftertwo recrystallizations from benzene. The yellow crystals had M. P. l191C. with decomposition.

Example B.N,N'-bis(2-benz0thiaz0lyl) oxumide A mixture of 1.5 g. ofZ-aminobenzothiazole and 1.46 g. of diethyl oxalate was heated underreflux for about two minutes. The solid product was removed from theflask and washed with methyl alcohol. After two recrystallizations frompyridine, the colorless crystals melted above 320 C.

Example C.2-(Z-benzotlziazolylhydrazono methylbenzothiazole A solutionof 1.7 g. (1 mol.) of beuzothiazole-Z- carboxaldehyde and 1.7 g. (1mol.) of Z-hydrazinobenzothiazole in 25 ml. of absolute ethyl alcoholwas heated at the refluxing temperature for 30 minutes. After chilling,the product was collected on a filter and washed with ethyl alcohol.After two recrystallizations from a mixture of 30 percent pyridine and70 percent ethyl alcohol, the yield was 37 percent, and the yellowcrystals melted at 271272 C. with decomposition.

Example D.1,5-bis(Z-benzothiazolylthio) pentane A mixture of 8.35 g.(0.05 mol.) of mercaptobenzothiazole and 5.75 g. (0.025 mol.) ofpentamethylene bromide was heated for two hours at C. A homogeneousliquid first formed but soon solidified to a glassy solid. The mixturewas retained at 135 C. for two hours. The solid product was dissolved inmethanol, decolorized with decolorizing carbon, filtered, and chilled.The solid that separated (4 g.) melted at 6 C. The higher melting solidis the salt which loses hydrogen bromide readily. A reaction carried outin methanol in the presence of sodium methoxide gave the same product.

Compound 16 can be prepared according to the method described in U. S.Patent 2,726,246, issued December 6, 1955.

Compound 21 was prepared in the manner shown in Example D above, byeacting together Z-mercaptobenzimidazole and ethylene bromide.

Compound 24 was prepared as follows: 3.7 g. of 2- aminobenzothiazole wasmixed with 2.1 ml. of diketene and allowed to stand. In about minutes, avigorous reaction took place. The mixture liquified and then turned to asolid. This solid was crystallized from alcohol to give a quantitativeyield of product melting at Compound 36 was prepared as follows: 6.0 g.of the sodium salt of Compound were dissolved in 100 ml. of watercontaining 5 g. of sodium carbonate. Phosgene was led into this solutionat 5 0 C. with a period of 1.5 hours. When the reaction mixture gave anegative diazo reaction, heating was discontinued and the desiredproduct recovered from the reaction mixture by the addition of an equalvolume of saturated salt solution. The yield of product was 4.3 g.

Compound 37, can be prepared by condensing 3-ethyl- 2(3)-benzothiazolonehydrozone (Chem. Abs, 22, 1358) with terephthalic aldehyde.

What we claim as our invention and desire secured by Letters Patent ofthe United States is:

1. A photographic gelatino-silver-halide developingout emulsionsensitized with a supersensitizing combination of at least onedicarbocyanine dye selected from those represented by the followinggeneral formula:

1'; wherein R and R each represents an alkyl group containing from 1 to2 carbon atoms, n represents a positive integer of from 1 to 2, Xrepresents an acid radical, Z represents the non-metallic atomsnecessary to complete a heterocyclic nucleus selected from the groupconsisting of those of the benzothiazole series, those of thenaphthothiazole series, those of the benzoselenazole series, those ofthe naphthoselenazole series, those of the benzoxazole series, those ofthe naphthoxazole series, those of the 2-quinoline series, those of the4-quinoline series, and those of the benzimidazole series, and Zrepresents the non-metallic atoms necessary to complete a heterocyclicnucleus selected from the group consisting of those of the benzoxazoleseries, those of the naphthoxazole series, those of the benzoselenazoleseries, those of the naphthoselenazole series, those of thebenzothiazole series, those of the naphthothiazole series, and those ofthe Z-quinoline series, and at least one heterocyclic base selected fromthose represented by the following general formula:

good stirring for wherein R and R each represents an alkyl groupcontaining from 1 to 2 carbon atoms, X represents an acid radical, and Zrepresents the non-metallic atoms necessary to complete a heterocyclicnucleus of the benzothiazole series, and at least one heterocyclic baseselected from those represented by the following general formula:

wherein Z represents the non-metallic atoms necessary to complete aheterocyclic nucleus selected from the group consisting of those of thethiazole series, those of the benzothiazole series, those of thenaphthothiazole series, those of the oxazole series, those of thebenzoxazole series, those of the naphthoxazole series, those of theselenazole series, those of the benzoselenazole series, those of thenaphthoselenazole series, those of the benzimidazole series, and thoseof the Z-quinoline series, a represents a positive integer of from 1 to2, D represents a divalent organic radical selected from the groupconsisting of a dithiaalkylene group containing from 1 to 5 carbonatoms, an alkylene group containing from 1 to 10 carbon atoms, anarylene group containing from 6 to 13 carbon atoms, a vinylene group, athio group, and an oxydirnethylene group.

3. A photographic gelatino-silver-halide developingout emulsionsensitized with a supersensitizing combination of at least onedicarbocyanine dye selected from those represented by the followinggeneral formula:

wherein R and R each represents an alkyl group containing from 1 to 2carbon atoms, X represents an acid radical, and Z represents thenon-metallic atoms necessary to complete a heteroeyclic nucleus of thebenzothiazole series, and at least one heterocyclic base selected fromthose represented by the following general formula:

in I Iii-R1 X wherein R and R each represents an alkyl group containingfrom 1 to 2 carbon atoms, X represents an acid radical, Z represents thenon-metallic atoms necessary to complete a heterocyclic nucleus of thebenzothiazole series, and Z represents the non-metallic atoms necessaryto complete a heterocyclic nucleus of the benzoxazole series, and atleast one heterocyclic base selected from those represented by thefollowing general formula:

wherein Z represents the non-metallic atoms necessary to complete aheterocyclic nucleus selected from the group consisting of those of thethiazole series, those of the benzothiazole series, those of thenaphthothiazole series, those of the oxazole series, those of thebenzoxazole series, those of the naphthoxazole series, those of theselenazole series, those of the benzoselenazole series, those of thenaphthoselenazole series, those of the benzimidazole series, and thoseof the Z-quinoline series, va! represents a positive integer of from 1to 2, D represents a divalent organic radical selected from the groupconsisting of a dithiaalkylene group containing from 1 to 5 carbonatoms, an alkylene group containing from 1 to carbon atoms, an arylenegroup containing from 6 to 13 carbon atoms, a vinylene group, a thiogroup, and an oxydimethylene group.

6. A photographic gelatino-silver-halide developingout emulsionsensitized with a supersensitizing combination of at least onedicarbocyanine dye selected from those represented by the followinggeneral formula:

wherein Z represents the non-metallic atoms necessary to complete aheterocyclic nucleus of the benzothiazole series and D represents abis(phen lene)methyl group.

7. A photographic g'elatino-silvcr-halide developingout emulsionsensitized with a supersensltizing combination of3,3'-diethyloxathiadicarbocyanine iodide and bis- [4-(2-benzothiazolyl)-phenyl] methane.

8. A photographic gelatino-silver-halide developingout emulsionsensitized with a supersensitizing combination of at least onedicarbocyanine dye selected from those represented by the followinggeneral formula:

wherein R and R each represents an alkyl group containing from 1 to 2carbon atoms, X represents an acid radical, and Z represents thenon-metallic atoms necessary to complete a heterocyclic nucleus of thebenzoselenazole series, and at least one heterocyclic base selected fromthose represented by the following general formula:

bl Exam-we wherein Z represents the non-metalic atoms necessary tocomplete a heterocyclic nucleus selected from the group consisting ofthose of the thiazole series, those of the benzothiazole series, thoseof the naphthothiazole series, those of the oxazole series, those of thebenzoxazole series, those of the naphthoxazole series, those of theselenazole series, those of the benzoselenazole series, those of thenaphthoselenazole series, those of the benzirnidazole series, and thoseof the Z-quinoline series, d represents a positive integer of from 1 to2, D represents a divalent organic radical selected from the groupconsisting of a dithiaalkylene group containing from 1 to 5 carbonatoms, an alkylene group containing from 1 to 10 carbon atoms, anarylene group containing from 6 to 13 carbon atoms, a vinylene group, athio group, and an oxydimethylene group.

9. A photographic gelatino-silver-halide developingout emulsionsensitized with a supersensitizing combination of at least onedicarbocyanine dye selected from those represented by the followinggeneral formula:

l b-R1 wherein R and R each represents an alkyl group containing from 1to 2 carbon atoms, X represents an acid radical, and Z represents thenon-metallic atoms necessary to complete a heterocyclic nucleus of thebenzoselenazole series, and at least one heterocyclic base selected fromthose represented by the following general formula:

References fitted in the file of this patent UNITED STATES PATENTS2,680,686 Van Dormael et al June 8, 1954

1. A PHOTOGRAPHIC GELATINO-SILVER-HALIDE DEVELOPINGOUT EMULSIONSENSITIZED WITH A SUPERSENITIZING COMBINATION OF AT LEAST ONEDICARBOCYANINE DYE SELECTED FROM THOSE REPRESENTED BY THE FOLLOWINGGENERAL FORMULA: